The present invention relates generally to a photo-detector, and more particularly to a two-mode InGaSb/GaSb strained-layer superlattice infrared photodetector.
At present, such general photodetectors as quantum well and superlattice photodetectors yield specific frequencies for specific amounts of energy. They use the transition between the lowest confined energy band of electrons(1C) and the highest confined energy band of a heavy hole (1HH) to produce a photoelectric current; therefore they cannot function as two-mode photodetectors. In order for a prior art photodetector to select between two different wavelengths, the prior art detector usually must be adapted to include two photodetectors and two filters. In addition, prior art tricolor photodetectors use a SiC:H/a-Si:H heterojunction and employ different active areas to absorb the light of different wavelengths: 575 nm, 530 nm, and 480 nm, all within the range of visible light only.